Picasso rotated the original painting by 90 degrees and incorporated some of its elements into the background of his masterpiece.

The discovery was first made by Sandra Webster-Cook, senior conservator at the Art Gallery of Ontario, which owns the 1902 painting. Looking closely at the surface, she noted unusual textures and colours peeking through cracks in the painting’s surface.

Different images of La Miséreuse accroupie, various elements contained in the paints.

That, however, was not the only surprise that lurked under the crouching woman. John Delaney, senior imaging scientist at Canada’s National Gallery of Art, then subjected the painting to another non-invasive procedure, called infrared reflectance hyperspectral imaging, which detects the varying transparency of paint layers.

Doing so, he found images of a disc and an arm hidden beneath the surface. The arm turned out to be particularly interesting – it was an exact replica of one Picasso painted in a 1902 watercolour called “Femme assise”.

Which painting came first, however, the oil or the watercolour remains – like the creator of the buried landscape – unknown. But perhaps not for long.

“We now are able to develop a chronology within the painting structure to tell a story about the artist's developing style and possible influences," says Webster-Cook.